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PSpice®
includes PSpice A/D, PSpice A/D Basics, and PSpice
User’s Guide

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Copyright © 1985-2000 Cadence Design Systems, Inc. All rights reserved.
Trademarks
Allegro, Ambit, BuildGates, Cadence, Cadence logo, Concept, Diva, Dracula, Gate
Ensemble, NC Verilog, OpenBook online documentation library, Orcad, Orcad
Capture, PSpice, SourceLink online customer support, SPECCTRA, Spectre, Vampire,
Verifault-XL, Verilog, Verilog-XL, and Virtuoso are registered trademarks of Cadence
Design Systems, Inc.
Affirma, Assura, Cierto, Envisia, Mercury Plus, Quickturn, Radium, Silicon Ensemble,
and SPECCTRAQuest are trademarks of Cadence Design Systems, Inc.
Alanza is a service mark of Cadence Design Systems, Inc.
All other brand and product names mentioned herein are used for identification
purposes only and are registered trademarks, trademarks, or service marks of their
respective holders.
Part Number 60-30-632
Second Edition 31 May 2000
Cadence PCB Systems Division (PSD) offices
PSD main office (Portland) (503) 671-9500
PSD Irvine office (949) 788-6080
PSD Japan office 81-45-682-5770
PSD UK office 44-1256-381-400
PSD customer support (877) 237-4911
PSD web site www.orcad.com
PSD customer support web page www.orcad.com/technical/technical.asp
PSD customer support email form www.orcad.com/technical/email_support.asp
Cadence PCB Systems Division
13221 SW 68th Parkway, Suite 200
Portland, OR 97223

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Contents
Before you begin xxv
Welcome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxv
How to use this guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxvi
Symbols and conventions . . . . . . . . . . . . . . . . . . . . . . . xxvi
Related documentation . . . . . . . . . . . . . . . . . . . . . . . . . xxvii
What this user’s guide covers . . . . . . . . . . . . . . . . . . . . . . . . xxx
PSpice A/D overview . . . . . . . . . . . . . . . . . . . . . . . . . . . xxxi
PSpice A/D Basics overview . . . . . . . . . . . . . . . . . . . . . . . xxxi
PSpice overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxxi
If you don’t have the standard PSpice A/D package . . . . . . . . . . xxxii
Comparison of the different versions of PSpice . . . . . . . . . . . xxxii
If you have PSpice A/D Lite . . . . . . . . . . . . . . . . . . . . . . xxxv
Limits of PSpice A/D Lite . . . . . . . . . . . . . . . . . . . . . xxxv
Minimum hardware requirements for running PSpice: . . . . . . . xxxv
What’s new . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxxvi
Part one Simulation primer
Chapter 1 Things you need to know 41
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
What is PSpice A/D? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Analyses you can run with PSpice A/D . . . . . . . . . . . . . . . . . . . 44
Basic analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
DC sweep & other DC calculations . . . . . . . . . . . . . . . . . . 44
AC sweep and noise . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Transient and Fourier . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Advanced multi-run analyses . . . . . . . . . . . . . . . . . . . . . . . 47
Parametric and temperature . . . . . . . . . . . . . . . . . . . . . . 47
Monte Carlo and sensitivity/worst-case . . . . . . . . . . . . . . . 48
Analyzing waveforms with PSpice . . . . . . . . . . . . . . . . . . . . . . 49

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What is waveform analysis? . . . . . . . . . . . . . . . . . . . . . . . 49
Using PSpice with Orcad programs . . . . . . . . . . . . . . . . . . . . . 50
Using Capture to prepare for simulation . . . . . . . . . . . . . . . . 50
What is the PSpice Stimulus Editor? . . . . . . . . . . . . . . . . . . 50
What is the PSpice Model Editor? . . . . . . . . . . . . . . . . . . . . 51
Files needed for simulation . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Files that Capture generates . . . . . . . . . . . . . . . . . . . . . . . 51
Netlist file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Circuit file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Other files that you can configure for simulation . . . . . . . . . . . 52
Model library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Stimulus file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Include file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Configuring model library, stimulus, and include files . . . . . . 54
Files that PSpice generates . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Waveform data file . . . . . . . . . . . . . . . . . . . . . . . . . . 55
PSpice output file . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Chapter 2 Simulation examples 57
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Example circuit creation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Finding out more about setting up your design . . . . . . . . . . . . 63
Running PSpice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Performing a bias point analysis . . . . . . . . . . . . . . . . . . . . . 64
Using the simulation output file . . . . . . . . . . . . . . . . . . . . . 66
Finding out more about bias point calculations . . . . . . . . . . . . 67
DC sweep analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Setting up and running a DC sweep analysis . . . . . . . . . . . . . . 68
Displaying DC analysis results . . . . . . . . . . . . . . . . . . . . . . 70
Finding out more about DC sweep analysis . . . . . . . . . . . . . . 73
Transient analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Finding out more about transient analysis . . . . . . . . . . . . . . . 78
AC sweep analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Setting up and running an AC sweep analysis . . . . . . . . . . . . . 79
AC sweep analysis results . . . . . . . . . . . . . . . . . . . . . . . . 81
Finding out more about AC sweep and noise analysis . . . . . . . . 83
Parametric analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Setting up and running the parametric analysis . . . . . . . . . . . . 85
Analyzing waveform families . . . . . . . . . . . . . . . . . . . . . . 87
Finding out more about parametric analysis . . . . . . . . . . . . . . 89
Performance analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
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Finding out more about performance analysis . . . . . . . . . . . . . . 92
Part two Design entry
Chapter 3 Preparing a design for simulation 95
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Checklist for simulation setup . . . . . . . . . . . . . . . . . . . . . . . . . 96
Typical simulation setup steps . . . . . . . . . . . . . . . . . . . . . . . 96
Advanced design entry and simulation setup steps . . . . . . . . . . . 97
When netlisting fails or the simulation does not start . . . . . . . . . . 98
Things to check in your design . . . . . . . . . . . . . . . . . . . . 98
Things to check in your system configuration . . . . . . . . . . . . 99
Using parts that you can simulate . . . . . . . . . . . . . . . . . . . . . . 100
Vendor-supplied parts . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Part naming conventions . . . . . . . . . . . . . . . . . . . . . . . 101
Finding the part that you want . . . . . . . . . . . . . . . . . . . 102
Passive parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
Breakout parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Behavioral parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Using global parameters and expressions for values . . . . . . . . . . . 107
Global parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Declaring and using a global parameter . . . . . . . . . . . . . . 107
Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Specifying expressions . . . . . . . . . . . . . . . . . . . . . . . . 109
Defining power supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
For the analog portion of your circuit . . . . . . . . . . . . . . . . . . 114
For A/D interfaces in mixed-signal circuits . . . . . . . . . . . . . . 114
Default digital power supplies . . . . . . . . . . . . . . . . . . . 114
Custom digital power supplies . . . . . . . . . . . . . . . . . . . 114
Defining stimuli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Analog stimuli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Using VSTIM and ISTIM . . . . . . . . . . . . . . . . . . . . . . . 116
If you want to specify multiple stimulus types . . . . . . . . . . 117
Digital stimuli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
Things to watch for . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Unmodeled parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Do this if the part in question is from the Orcad libraries . . . . 119
Check for this if the part in question is custom-built . . . . . . . 121
Unconfigured model, stimulus, or include files . . . . . . . . . . . . 121
Check for this . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Unmodeled pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
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Check for this . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Missing ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Check for this . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Missing DC path to ground . . . . . . . . . . . . . . . . . . . . . . . . 124
Check for this . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
Chapter 4 Creating and editing models 125
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
What are models? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Models defined as model parameter sets . . . . . . . . . . . . . . 127
Models defined as subcircuit netlists . . . . . . . . . . . . . . . . 127
How are models organized? . . . . . . . . . . . . . . . . . . . . . . . . . 128
Model libraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Model library configuration . . . . . . . . . . . . . . . . . . . . . . . 129
Global vs. design models and libraries . . . . . . . . . . . . . . . . . 129
Nested model libraries . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Orcad-provided models . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Tools to create and edit models . . . . . . . . . . . . . . . . . . . . . . . . 131
Ways to create and edit models . . . . . . . . . . . . . . . . . . . . . . . . 132
Using the Model Editor to edit models . . . . . . . . . . . . . . . . . . . 134
Ways to use the Model Editor . . . . . . . . . . . . . . . . . . . . . . 135
Model Editor-supported device types . . . . . . . . . . . . . . . . . . 136
Ways To Characterize Models . . . . . . . . . . . . . . . . . . . . . . 137
Creating models from data sheet information . . . . . . . . . . . 137
Analyzing the effect of model parameters
on device characteristics . . . . . . . . . . . . . . . . . . . 138
How to fit models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Running the Model Editor alone . . . . . . . . . . . . . . . . . . . . . 140
Starting the Model Editor . . . . . . . . . . . . . . . . . . . . . . . 140
Enabling and disabling automatic part creation . . . . . . . . . . 141
Saving global models (and parts) . . . . . . . . . . . . . . . . . . 141
Running the Model Editor from the schematic page editor . . . . . . 142
What is an instance model? . . . . . . . . . . . . . . . . . . . . . . 142
Starting the Model Editor . . . . . . . . . . . . . . . . . . . . . . . 143
Saving design models . . . . . . . . . . . . . . . . . . . . . . . . . 143
What happens if you don’t save the instance model . . . . . . . . 144
The Model Editor tutorial . . . . . . . . . . . . . . . . . . . . . . . . . 145
Creating the half-wave rectifier design . . . . . . . . . . . . . . . 145
Using the Model Editor to edit the D1 diode model . . . . . . . . 146
Entering data sheet information . . . . . . . . . . . . . . . . . . . 146
Extracting model parameters . . . . . . . . . . . . . . . . . . . . . 149
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Adding curves for more than one temperature . . . . . . . . . . 149
Completing the model definition . . . . . . . . . . . . . . . . . . 150
Editing model text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Editing .MODEL definitions . . . . . . . . . . . . . . . . . . . . . 152
Editing .SUBCKT definitions . . . . . . . . . . . . . . . . . . . . 152
Changing the model name . . . . . . . . . . . . . . . . . . . . . . 152
Starting the Model Editor from the schematic page
editor in Capture . . . . . . . . . . . . . . . . . . . . . . . . . 152
What is an instance model? . . . . . . . . . . . . . . . . . . . . . 153
Starting the Model Editor . . . . . . . . . . . . . . . . . . . . . . 153
Saving design models . . . . . . . . . . . . . . . . . . . . . . . . 154
Example: editing a Q2N2222 instance model . . . . . . . . . . . . . . 155
Starting the Model Editor . . . . . . . . . . . . . . . . . . . . . . 155
Editing the Q2N2222-X model instance . . . . . . . . . . . . . . 155
Saving the edits and updating the schematic . . . . . . . . . . . 156
Using the Create Subcircuit command . . . . . . . . . . . . . . . . . . . 156
Changing the model reference to an existing model definition . . . . . . 158
Reusing instance models . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
Reusing instance models in the same schematic . . . . . . . . . . . . 159
Making instance models available to all designs . . . . . . . . . . . 160
Configuring model libraries . . . . . . . . . . . . . . . . . . . . . . . . . 161
The Libraries and Include Files tabs . . . . . . . . . . . . . . . . . . . 161
How PSpice uses model libraries . . . . . . . . . . . . . . . . . . . . 162
Search order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
Handling duplicate model names . . . . . . . . . . . . . . . . . . 163
Adding model libraries to the configuration . . . . . . . . . . . . . . 163
Changing design and global scope . . . . . . . . . . . . . . . . . . . 164
Changing model library search order . . . . . . . . . . . . . . . . . . 165
Changing the library search path . . . . . . . . . . . . . . . . . . . . 166
Chapter 5 Creating parts for models 167
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
What’s different about parts used for simulation? . . . . . . . . . . . . . 169
Ways to create parts for models . . . . . . . . . . . . . . . . . . . . . . . 170
Preparing your models for part creation . . . . . . . . . . . . . . . . . . 171
Using the Model Editor to create parts . . . . . . . . . . . . . . . . . . . 172
Starting the Model Editor . . . . . . . . . . . . . . . . . . . . . . . . . 172
Setting up automatic part creation . . . . . . . . . . . . . . . . . . . 173
Basing new parts on a custom set of parts . . . . . . . . . . . . . . . . . 174
Editing part graphics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
How Capture places parts . . . . . . . . . . . . . . . . . . . . . . . . 176
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Defining grid spacing . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
Grid spacing for graphics . . . . . . . . . . . . . . . . . . . . . . . 177
Grid spacing for pins . . . . . . . . . . . . . . . . . . . . . . . . . 177
Attaching models to parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
MODEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
Defining part properties needed for simulation . . . . . . . . . . . . . . 180
PSPICETEMPLATE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
PSPICETEMPLATE syntax . . . . . . . . . . . . . . . . . . . . . . 181
PSPICETEMPLATE examples . . . . . . . . . . . . . . . . . . . . 184
IO_LEVEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
MNTYMXDLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
PSPICEDEFAULTNET . . . . . . . . . . . . . . . . . . . . . . . . . . 190
Chapter 6 Analog behavioral modeling 191
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
Overview of analog behavioral modeling . . . . . . . . . . . . . . . . . . 192
The ABM.OLB part library file . . . . . . . . . . . . . . . . . . . . . . . . 193
Placing and specifying ABM parts . . . . . . . . . . . . . . . . . . . . . . 194
Net names and device names in ABM expressions . . . . . . . . . . 194
Forcing the use of a global definition . . . . . . . . . . . . . . . . . . 195
ABM part templates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
Control system parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Basic components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
Limiters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
Chebyshev filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Integrator and differentiator . . . . . . . . . . . . . . . . . . . . . . . 204
Table look-up parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Laplace transform part . . . . . . . . . . . . . . . . . . . . . . . . . . 208
Math functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
ABM expression parts . . . . . . . . . . . . . . . . . . . . . . . . . . 212
An instantaneous device example: modeling a triode . . . . . . . . . 215
PSpice-equivalent parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
Implementation of PSpice-equivalent parts . . . . . . . . . . . . . . . 219
Modeling mathematical or instantaneous relationships . . . . . . . . 220
EVALUE and GVALUE parts . . . . . . . . . . . . . . . . . . . . 220
EMULT, GMULT, ESUM, and GSUM . . . . . . . . . . . . . . . . 222
Lookup tables (ETABLE and GTABLE) . . . . . . . . . . . . . . . . . 223
Frequency-domain device models . . . . . . . . . . . . . . . . . . . . 225
Laplace transforms (LAPLACE) . . . . . . . . . . . . . . . . . . . . . 225
Frequency response tables (EFREQ and GFREQ) . . . . . . . . . . . 227
Cautions and recommendations for simulation and analysis . . . . . . . 230
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Instantaneous device modeling . . . . . . . . . . . . . . . . . . . . . 230
Frequency-domain parts . . . . . . . . . . . . . . . . . . . . . . . . . 231
Laplace transforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Non-causality and Laplace transforms . . . . . . . . . . . . . . . 233
Chebyshev filters . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
Frequency tables . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
Trading off computer resources for accuracy . . . . . . . . . . . . . 235
Basic controlled sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
Creating custom ABM parts . . . . . . . . . . . . . . . . . . . . . . . 236
Chapter 7 Digital device modeling 237
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Functional behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
Digital primitive syntax . . . . . . . . . . . . . . . . . . . . . . . 242
Timing characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
Timing model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
Treatment of unspecified propagation delays . . . . . . . . . 248
Treatment of unspecified timing constraints . . . . . . . . . . . . 249
Propagation delay calculation . . . . . . . . . . . . . . . . . . . . . . 250
Inertial and transport delay . . . . . . . . . . . . . . . . . . . . . . . 251
Inertial delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
Transport delay . . . . . . . . . . . . . . . . . . . . . . . . . 252
Input/Output characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 253
Input/Output model . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
Defining Output Strengths . . . . . . . . . . . . . . . . . . . . . . . . 257
Configuring the strength scale . . . . . . . . . . . . . . . . . . . . 258
Determining the strength of a device output . . . . . . . . . . . 258
Controlling overdrive . . . . . . . . . . . . . . . . . . . . . . . . 259
Charge storage nets . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
Creating your own interface subcircuits for
additional technologies . . . . . . . . . . . . . . . . . . . . . 261
Creating a digital model using the PINDLY and LOGICEXP
primitives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
Digital primitives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
Logic expression (LOGICEXP primitive) . . . . . . . . . . . . . . . . 268
Pin-to-pin delay (PINDLY primitive) . . . . . . . . . . . . . . . . . . 270
BOOLEAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
PINDLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
Constraint checker (CONSTRAINT primitive) . . . . . . . . . . . . . 273
Setup_Hold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274
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Width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
Freq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
74160 example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
Part three Setting up and running analyses
Chapter 8 Setting up analyses and starting simulation 281
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281
Analysis types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
Setting up analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
Execution order for standard analyses . . . . . . . . . . . . . . . . . 285
Output variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286
Modifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
Starting a simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
Creating a simulation netlist . . . . . . . . . . . . . . . . . . . . . . . 292
Using netlisting templates . . . . . . . . . . . . . . . . . . . . . . 293
Passing parameters to subcircuits . . . . . . . . . . . . . . . . . . 294
Creating the netlist . . . . . . . . . . . . . . . . . . . . . . . . . . 295
Customizing the hierarchical netlist . . . . . . . . . . . . . . . . . 297
Creating subcircuit netlists . . . . . . . . . . . . . . . . . . . . . . 300
Specifying alternate netlist templates . . . . . . . . . . . . . . . . 300
Starting a simulation from Capture . . . . . . . . . . . . . . . . . . . 301
Starting a simulation outside of Capture . . . . . . . . . . . . . . . . 302
Setting up batch simulations . . . . . . . . . . . . . . . . . . . . . . . 302
Multiple simulation setups within one circuit file . . . . . . . . . 302
Running simulations with multiple circuit files . . . . . . . . . . 303
The PSpice simulation window . . . . . . . . . . . . . . . . . . . . . 303
Interacting with a simulation . . . . . . . . . . . . . . . . . . . . . . . . . 307
What the various versions of PSpice support . . . . . . . . . . . 307
Extending a transient analysis . . . . . . . . . . . . . . . . . . . . . . 308
Interrupting a simulation . . . . . . . . . . . . . . . . . . . . . . . . . 310
Scheduling changes to runtime parameters . . . . . . . . . . . . . . . 313
PSpice command syntax for scheduling parameter changes . . . 313
Using the Simulation Manager . . . . . . . . . . . . . . . . . . . . . . . . 315
Overview of the Simulation Manager . . . . . . . . . . . . . . . . . . 315
Accessing the Simulation Manager . . . . . . . . . . . . . . . . . 316
Understanding the information in the Simulation Manager . . . 316
What the various versions of PSpice support . . . . . . . . . . . 319
How the Simulation Manager handles errors during simulation 319
Setting up multiple simulations . . . . . . . . . . . . . . . . . . . . . 320
Starting, stopping, and pausing simulations . . . . . . . . . . . . . . 320
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Attaching PSpice to a simulation . . . . . . . . . . . . . . . . . . . . 321
Setting options in the Simulation Manager . . . . . . . . . . . . . . . 322
Chapter 9 DC analyses 325
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
DC Sweep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326
Minimum requirements to run a DC sweep analysis . . . . . . . . . 326
Overview of DC sweep . . . . . . . . . . . . . . . . . . . . . . . . . . 328
Setting up a DC stimulus . . . . . . . . . . . . . . . . . . . . . . . . . 330
Nested DC sweeps . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331
Curve families for DC sweeps . . . . . . . . . . . . . . . . . . . . . . 332
Bias point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334
Minimum requirements to run a bias point analysis . . . . . . . . . 334
Overview of bias point . . . . . . . . . . . . . . . . . . . . . . . . . . 334
Small-signal DC transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . 336
Minimum requirements to run a small-signal DC transfer analysis . 336
Overview of small-signal DC transfer . . . . . . . . . . . . . . . . . . 337
DC sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339
Minimum requirements to run a DC sensitivity analysis . . . . . . . 339
Overview of DC sensitivity . . . . . . . . . . . . . . . . . . . . . . . . 340
Chapter 10 AC analyses 341
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341
AC sweep analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342
Setting up and running an AC sweep . . . . . . . . . . . . . . . . . . 342
What is AC sweep? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342
Setting up an AC stimulus . . . . . . . . . . . . . . . . . . . . . . . . 343
Setting up an AC analysis . . . . . . . . . . . . . . . . . . . . . . . . 345
AC sweep setup in example.opj . . . . . . . . . . . . . . . . . . . . . 347
How PSpice treats nonlinear devices . . . . . . . . . . . . . . . . . . 349
What’s required to transform a device into a linear circuit . . . . 349
What PSpice does . . . . . . . . . . . . . . . . . . . . . . . . . . . 349
Example: nonlinear behavioral modeling block . . . . . . . . . . 349
Noise analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351
Setting up and running a noise analysis . . . . . . . . . . . . . . . . 351
What is noise analysis? . . . . . . . . . . . . . . . . . . . . . . . . . . 352
How PSpice calculates total output and input noise . . . . . . . 352
Setting up a noise analysis . . . . . . . . . . . . . . . . . . . . . . . . 353
Analyzing Noise in the Probe window . . . . . . . . . . . . . . . . . 355
About noise units . . . . . . . . . . . . . . . . . . . . . . . . . . . 356
Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356
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Chapter 11 Transient analysis 359
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359
Overview of transient analysis . . . . . . . . . . . . . . . . . . . . . . . . 360
Minimum requirements to run a transient analysis . . . . . . . . . . 360
Minimum circuit design requirements . . . . . . . . . . . . . . . 360
Minimum program setup requirements . . . . . . . . . . . . . . 360
Defining a time-based stimulus . . . . . . . . . . . . . . . . . . . . . . . 362
Overview of stimulus generation . . . . . . . . . . . . . . . . . . . . 362
The Stimulus Editor utility . . . . . . . . . . . . . . . . . . . . . . . . . . 364
Stimulus files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
Configuring stimulus files . . . . . . . . . . . . . . . . . . . . . . . . 365
Starting the Stimulus Editor . . . . . . . . . . . . . . . . . . . . . . . 365
Defining stimuli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366
Example: piecewise linear stimulus . . . . . . . . . . . . . . . . . 366
Example: sine wave sweep . . . . . . . . . . . . . . . . . . . . . . 367
Creating new stimulus symbols . . . . . . . . . . . . . . . . . . . . . 369
Editing a stimulus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370
To edit an existing stimulus . . . . . . . . . . . . . . . . . . . . . 370
To edit a PWL stimulus . . . . . . . . . . . . . . . . . . . . . . . . 370
To select a time and value scale factor for PWL stimuli . . . . . . 370
Deleting and removing traces . . . . . . . . . . . . . . . . . . . . . . 371
Manual stimulus configuration . . . . . . . . . . . . . . . . . . . . . . 371
To manually configure a stimulus . . . . . . . . . . . . . . . . . . 371
Transient (time) response . . . . . . . . . . . . . . . . . . . . . . . . . . . 373
Internal time steps in transient analyses . . . . . . . . . . . . . . . . . . . 376
Switching circuits in transient analyses . . . . . . . . . . . . . . . . . . . 377
Plotting hysteresis curves . . . . . . . . . . . . . . . . . . . . . . . . . . . 377
Fourier components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
Chapter 12 Parametric and temperature analysis 381
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381
Parametric analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382
Minimum requirements to run a parametric analysis . . . . . . . . . 382
Overview of parametric analysis . . . . . . . . . . . . . . . . . . . . . 383
RLC filter example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384
Entering the design . . . . . . . . . . . . . . . . . . . . . . . . . . 384
Running the simulation . . . . . . . . . . . . . . . . . . . . . . . . 385
Using performance analysis to plot overshoot and rise time . . . 385
Example: frequency response vs. arbitrary parameter . . . . . . . . . 388
Setting up the circuit . . . . . . . . . . . . . . . . . . . . . . . . . 388
Temperature analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391
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Minimum requirements to run a temperature analysis . . . . . . . . 391
Overview of temperature analysis . . . . . . . . . . . . . . . . . . . . 392
Chapter 13 Monte Carlo and sensitivity/worst-case analyses 393
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393
Statistical analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394
Overview of statistical analyses . . . . . . . . . . . . . . . . . . . . . 394
Output control for statistical analyses . . . . . . . . . . . . . . . . . . 395
Model parameter values reports . . . . . . . . . . . . . . . . . . . . . 395
Waveform reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396
Collating functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
Temperature considerations in statistical analyses . . . . . . . . . . 398
Monte Carlo analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
Reading the summary report . . . . . . . . . . . . . . . . . . . . 401
Example: Monte Carlo analysis of a pressure sensor . . . . . . . . . 403
Drawing the schematic . . . . . . . . . . . . . . . . . . . . . . . . 403
Defining part values . . . . . . . . . . . . . . . . . . . . . . . . . 404
Setting up the parameters . . . . . . . . . . . . . . . . . . . . . . 405
Using resistors with models . . . . . . . . . . . . . . . . . . . . . 406
Saving the design . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
Defining tolerances for the resistor models . . . . . . . . . . . . 407
Setting up the analyses . . . . . . . . . . . . . . . . . . . . . . . . 409
Running the analysis and viewing the results . . . . . . . . . . . 410
Monte Carlo Histograms . . . . . . . . . . . . . . . . . . . . . . . . . 411
Chebyshev filter example . . . . . . . . . . . . . . . . . . . . . . 411
Creating models for Monte Carlo analysis . . . . . . . . . . . . . 412
Setting up the analysis . . . . . . . . . . . . . . . . . . . . . . . . 412
Creating histograms . . . . . . . . . . . . . . . . . . . . . . . . . 413
Copying histogram data . . . . . . . . . . . . . . . . . . . . . . . 416
Worst-case analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
Overview of worst-case analysis . . . . . . . . . . . . . . . . . . . . . 417
Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418
Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418
Caution: An important condition for correct worst-case analysis 419
Worst-case analysis example . . . . . . . . . . . . . . . . . . . . . . . 420
Tips and other useful information . . . . . . . . . . . . . . . . . . . . 424
VARY BOTH, VARY DEV, and VARY LOT . . . . . . . . . . . . 424
Gaussian distributions . . . . . . . . . . . . . . . . . . . . . . . . 425
YMAX collating function . . . . . . . . . . . . . . . . . . . . . . . 425
RELTOL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425
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Sensitivity analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 425
Manual optimization . . . . . . . . . . . . . . . . . . . . . . . . . 425
Monte Carlo analysis . . . . . . . . . . . . . . . . . . . . . . . . . 426
Chapter 14 Digital simulation 427
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427
What is digital simulation? . . . . . . . . . . . . . . . . . . . . . . . . . . 428
Steps for simulating digital circuits . . . . . . . . . . . . . . . . . . . . . 428
Concepts you need to understand . . . . . . . . . . . . . . . . . . . . . . 429
States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 429
Strengths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430
Defining a digital stimulus . . . . . . . . . . . . . . . . . . . . . . . . . . 431
Using the DIGSTIMn part . . . . . . . . . . . . . . . . . . . . . . . . . 432
Defining input signals using the Stimulus Editor . . . . . . . . . . . 432
Defining clock transitions . . . . . . . . . . . . . . . . . . . . . . . 432
Defining signal transitions . . . . . . . . . . . . . . . . . . . . . . 433
Defining bus transitions . . . . . . . . . . . . . . . . . . . . . . . 435
Adding loops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
Using the DIGCLOCK part . . . . . . . . . . . . . . . . . . . . . . . . 439
Using STIM1, STIM4, STIM8 and STIM16 parts . . . . . . . . . . . . 439
Using the FILESTIMn parts . . . . . . . . . . . . . . . . . . . . . . . . 441
Defining simulation time . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
Adjusting simulation parameters . . . . . . . . . . . . . . . . . . . . . . . 444
Selecting propagation delays . . . . . . . . . . . . . . . . . . . . . . . 445
Circuit-wide propagation delays . . . . . . . . . . . . . . . . . . 445
Part instance propagation delays . . . . . . . . . . . . . . . . . . 445
Initializing flip-flops . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446
Starting the simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446
Analyzing results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447
Adding digital signals to a plot . . . . . . . . . . . . . . . . . . . . . . 448
Adding buses to a waveform plot . . . . . . . . . . . . . . . . . . . . 450
Tracking timing violations and hazards . . . . . . . . . . . . . . . . . 452
Persistent hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . 452
Simulation condition messages . . . . . . . . . . . . . . . . . . . 454
Output control options . . . . . . . . . . . . . . . . . . . . . . . . 457
Severity levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 457
Chapter 15 Mixed analog/digital simulation 459
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459
Interconnecting analog and digital parts . . . . . . . . . . . . . . . . . . 460
Interface subcircuit selection by PSpice . . . . . . . . . . . . . . . . . . . 461
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Level 1 interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 462
Level 2 interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464
Setting the default A/D interface . . . . . . . . . . . . . . . . . . . . 465
Specifying digital power supplies . . . . . . . . . . . . . . . . . . . . . . 466
Default power supply selection by PSpice A/D . . . . . . . . . . . . 466
Creating custom digital power supplies . . . . . . . . . . . . . . . . 467
Overriding CD4000 power supply voltage throughout a design 469
Creating a secondary CD4000, TTL, or ECL power supply . . . 470
Interface generation and node names . . . . . . . . . . . . . . . . . . . . 471
Chapter 16 Digital worst-case timing analysis 475
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475
Digital worst-case timing . . . . . . . . . . . . . . . . . . . . . . . . . . . 476
Digital worst-case analysis compared to analog worst-case analysis 477
Starting digital worst-case timing analysis . . . . . . . . . . . . . . . . . 478
Simulator representation of timing ambiguity . . . . . . . . . . . . . . . 478
Propagation of timing ambiguity . . . . . . . . . . . . . . . . . . . . . . 480
Identification of timing hazards . . . . . . . . . . . . . . . . . . . . . . . 481
Convergence hazard . . . . . . . . . . . . . . . . . . . . . . . . . . . 481
Critical hazard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 482
Cumulative ambiguity hazard . . . . . . . . . . . . . . . . . . . . . . 483
Reconvergence hazard . . . . . . . . . . . . . . . . . . . . . . . . . . 485
Glitch suppression due to inertial delay . . . . . . . . . . . . . . . . . . 487
Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488
Part four Viewing results
Chapter 17 Analyzing waveforms 493
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
Overview of waveform analysis . . . . . . . . . . . . . . . . . . . . . . . 494
Elements of a plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495
Elements of a Probe window . . . . . . . . . . . . . . . . . . . . . . . 496
Managing multiple Probe windows . . . . . . . . . . . . . . . . . . . 497
Printing multiple windows . . . . . . . . . . . . . . . . . . . . . 497
Toggling between display modes . . . . . . . . . . . . . . . . . . 497
Keeping the Probe window visible at all times . . . . . . . . . . 498
Setting up waveform analysis . . . . . . . . . . . . . . . . . . . . . . . . 499
Setting up colors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 499
Editing display and print colors in the PSPICE.INI file . . . . . . 499
Configuring trace color schemes . . . . . . . . . . . . . . . . . . 501
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Viewing waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
Setting up waveform display from Capture . . . . . . . . . . . . . . 502
Viewing waveforms while simulating . . . . . . . . . . . . . . . . . . 503
Configuring update intervals . . . . . . . . . . . . . . . . . . . . 504
Interacting with waveform analysis during simulation . . . . . . 504
Pausing a simulation and viewing waveforms . . . . . . . . . . . 505
Using schematic page markers to add traces . . . . . . . . . . . . . . 506
Using display control . . . . . . . . . . . . . . . . . . . . . . . . . . . 509
Using plot window templates . . . . . . . . . . . . . . . . . . . . . . 512
Limiting waveform data file size . . . . . . . . . . . . . . . . . . . . . 525
Limiting file size using markers . . . . . . . . . . . . . . . . . . . 525
Limiting file size by excluding internal subcircuit data . . . . . . 528
Limiting file size by suppressing the first part
of simulation output . . . . . . . . . . . . . . . . . . . . . 528
Using simulation data from multiple files . . . . . . . . . . . . . . . 529
Appending waveform data files . . . . . . . . . . . . . . . . . . . 529
Adding traces from specific loaded waveform data files . . . . . 530
Saving simulation results in ASCII format . . . . . . . . . . . . . . . 531
Analog example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 533
Running the simulation . . . . . . . . . . . . . . . . . . . . . . . . 533
Displaying voltages on nets . . . . . . . . . . . . . . . . . . . . . 535
Mixed analog/digital tutorial . . . . . . . . . . . . . . . . . . . . . . . . . 536
About digital states . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536
About the oscillator circuit . . . . . . . . . . . . . . . . . . . . . . . . 537
Setting up the design . . . . . . . . . . . . . . . . . . . . . . . . . . . 537
Running the simulation . . . . . . . . . . . . . . . . . . . . . . . . . . 538
Analyzing simulation results . . . . . . . . . . . . . . . . . . . . . . . 538
User interface features for waveform analysis . . . . . . . . . . . . . . . 541
Zoom regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541
Scrolling traces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543
Sizing digital plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . 544
Modifying trace expressions and labels . . . . . . . . . . . . . . . . . 545
Moving and copying trace names and expressions . . . . . . . . . . 546
Copying and moving labels . . . . . . . . . . . . . . . . . . . . . . . . 547
Tabulating trace data values . . . . . . . . . . . . . . . . . . . . . . . 548
Using cursors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549
Displaying cursors . . . . . . . . . . . . . . . . . . . . . . . . . . . 549
Moving cursors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 550
Applying cursors to a different trace . . . . . . . . . . . . . . . . 551
Example: using cursors . . . . . . . . . . . . . . . . . . . . . . . . 552
Tracking digital simulation messages . . . . . . . . . . . . . . . . . . . . 554
Message tracking from the message summary . . . . . . . . . . . . . 554
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Contents
The Simulation Message Summary dialog box . . . . . . . . . . 554
Persistent hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . 555
Message tracking from the waveform . . . . . . . . . . . . . . . . . . 556
Trace expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 556
Basic output variable form . . . . . . . . . . . . . . . . . . . . . . . . 557
Output variable form for device terminals . . . . . . . . . . . . . . . 558
Analog trace expressions . . . . . . . . . . . . . . . . . . . . . . . . . 564
Trace expression aliases . . . . . . . . . . . . . . . . . . . . . . . 564
Arithmetic functions . . . . . . . . . . . . . . . . . . . . . . . . . 564
Rules for numeric values suffixes . . . . . . . . . . . . . . . . . . 566
Digital trace expressions . . . . . . . . . . . . . . . . . . . . . . . . . 567
Chapter 18 Other output options 571
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 571
Viewing analog results in the PSpice window . . . . . . . . . . . . . . . 572
Writing additional results to the PSpice output file . . . . . . . . . . . . 573
Generating plots of voltage and current values . . . . . . . . . . . . 573
Generating tables of voltage and current values . . . . . . . . . . . . 574
Generating tables of digital state changes . . . . . . . . . . . . . . . 575
Creating test vector files . . . . . . . . . . . . . . . . . . . . . . . . . . . 576
Appendix A Setting initial state 577
Appendix overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 577
Save and load bias point . . . . . . . . . . . . . . . . . . . . . . . . . . . 578
Save bias point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578
Load bias point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 579
Setpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 580
Setting initial conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . 582
Appendix B Convergence and “time step too small errors” 583
Appendix overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 583
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 584
Newton-Raphson requirements . . . . . . . . . . . . . . . . . . . . . 584
Is there a solution? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 585
Are the Equations Continuous? . . . . . . . . . . . . . . . . . . . . . 586
Are the derivatives correct? . . . . . . . . . . . . . . . . . . . . . 586
Is the initial approximation close enough? . . . . . . . . . . . . . . . 587
Bias point and DC sweep . . . . . . . . . . . . . . . . . . . . . . . . . . . 589
Semiconductors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 589
Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 590
Behavioral modeling expressions . . . . . . . . . . . . . . . . . . . . 591
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Contents
Transient analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 592
Skipping the bias point . . . . . . . . . . . . . . . . . . . . . . . . . . 593
The dynamic range of TIME . . . . . . . . . . . . . . . . . . . . . . . 593
Failure at the first time step . . . . . . . . . . . . . . . . . . . . . . . . 594
Parasitic capacitances . . . . . . . . . . . . . . . . . . . . . . . . . . . 595
Inductors and transformers . . . . . . . . . . . . . . . . . . . . . . . . 595
Bipolar transistors substrate junction . . . . . . . . . . . . . . . . . . 596
Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 597
Index 599
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19. Pspug.book Page xix Tuesday, May 16, 2000 1:17 PM
Figures
Figure 1 User-configurable data files that PSpice A/D reads . . . . . . . . . . . . . 52
Figure 2 Diode clipper circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Figure 3 Connection points. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Figure 4 PSpice simulation output window. . . . . . . . . . . . . . . . . . . . . . . 64
Figure 5 Simulation output file. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Figure 6 DC sweep analysis settings. . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Figure 7 Probe window. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Figure 8 Clipper circuit with voltage marker on net Out. . . . . . . . . . . . . . . . 71
Figure 9 Voltage at In, Mid, and Out. . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Figure 10 Trace legend with cursors activated. . . . . . . . . . . . . . . . . . . . . . 72
Figure 11 Trace legend with V(Mid) symbol outlined. . . . . . . . . . . . . . . . . . 72
Figure 12 Voltage difference at V(In) = 4 volts. . . . . . . . . . . . . . . . . . . . . . 73
Figure 13 Diode clipper circuit with a voltage stimulus. . . . . . . . . . . . . . . . . 74
Figure 14 Stimulus Editor window. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Figure 15 Transient analysis simulation settings. . . . . . . . . . . . . . . . . . . . . 76
Figure 16 Sinusoidal input and clipped output waveforms. . . . . . . . . . . . . . . 77
Figure 17 Clipper circuit with AC stimulus. . . . . . . . . . . . . . . . . . . . . . . . 79
Figure 18 AC sweep and noise analysis simulation settings. . . . . . . . . . . . . . . 80
Figure 19 dB magnitude curves for “gain” at Mid and Out. . . . . . . . . . . . . . . 82
Figure 20 Bode plot of clipper’s frequency response. . . . . . . . . . . . . . . . . . . 83
Figure 21 Clipper circuit with global parameter Rval. . . . . . . . . . . . . . . . . . 84
Figure 22 Parametric simulation settings. . . . . . . . . . . . . . . . . . . . . . . . . . 86
Figure 23 Small signal response as R1 is varied from 100Ω to 10 kΩ . . . . . . . . . 87
Figure 24 Small signal frequency response at 100 and 10 kΩ input resistance. . . . 89
Figure 25 Performance analysis plots of bandwidth and gain vs. Rval. . . . . . . . . 91
Figure 26 Relationship of the Model Editor to Capture and PSpice. . . . . . . . . . 134
Figure 27 Process and data flow for the Model Editor. . . . . . . . . . . . . . . . . 137
Figure 28 Model Editor workspace with data for a bipolar transistor. . . . . . . . 138
Figure 29 Design for a half-wave rectifier. . . . . . . . . . . . . . . . . . . . . . . . 145
Figure 30 Model characteristics and parameter values for DbreakX. . . . . . . . . 147
Figure 31 Assorted device characteristic curves for a diode. . . . . . . . . . . . . . 149
Figure 32 Forward Current device curve at two temperatures. . . . . . . . . . . . 150

20. Pspug.book Page xx Tuesday, May 16, 2000 1:17 PM
Figures
Figure 33 Rules for pin callout in subcircuit templates. . . . . . . . . . . . . . . . . 187
Figure 34 LOPASS filter example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Figure 35 HIPASS filter part example. . . . . . . . . . . . . . . . . . . . . . . . . . . 202
Figure 36 BANDPASS filter part example. . . . . . . . . . . . . . . . . . . . . . . . 203
Figure 37 BANDREJ filter part example. . . . . . . . . . . . . . . . . . . . . . . . . 203
Figure 38 FTABLE part example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
Figure 39 LAPLACE part example one. . . . . . . . . . . . . . . . . . . . . . . . . . 209
Figure 40 Viewing gain and phase characteristics of a lossy integrator. . . . . . . . 209
Figure 41 LAPLACE part example two. . . . . . . . . . . . . . . . . . . . . . . . . . 209
Figure 42 ABM expression part example one. . . . . . . . . . . . . . . . . . . . . . 213
Figure 43 ABM expression part example two. . . . . . . . . . . . . . . . . . . . . . 213
Figure 44 ABM expression part example three. . . . . . . . . . . . . . . . . . . . . . 214
Figure 45 ABM expression part example four. . . . . . . . . . . . . . . . . . . . . . 214
Figure 46 Triode circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
Figure 47 Triode subcircuit producing a family of I-V curves. . . . . . . . . . . . . 217
Figure 48 EVALUE part example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
Figure 49 GVALUE part example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
Figure 50 EMULT part example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
Figure 51 GMULT part example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
Figure 52 EFREQ part example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
Figure 53 Voltage multiplier circuit (mixer). . . . . . . . . . . . . . . . . . . . . . . 230
Figure 54 Elements of a digital device definition . . . . . . . . . . . . . . . . . . . 243
Figure 55 Level 1 and 0 strength determination. . . . . . . . . . . . . . . . . . . . . 258
Figure 56 PSpice simulation window . . . . . . . . . . . . . . . . . . . . . . . . . . 305
Figure 57 Example schematic EXAMPLE.OPJ. . . . . . . . . . . . . . . . . . . . . . 329
Figure 58 Curve family example schematic. . . . . . . . . . . . . . . . . . . . . . . 332
Figure 59 Device curve family. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333
Figure 60 Operating point determination for each member of the curve family. . . 333
Figure 61 Circuit diagram for EXAMPLE.OPJ. . . . . . . . . . . . . . . . . . . . . . 347
Figure 62 AC analysis setup for EXAMPLE.OPJ. . . . . . . . . . . . . . . . . . . . . 348
Figure 63 Device and total noise traces for EXAMPLE.DSN. . . . . . . . . . . . . . 357
Figure 64 Transient analysis setup for EXAMPLE.OPJ. . . . . . . . . . . . . . . . . 374
Figure 65 Example schematic EXAMPLE.OPJ. . . . . . . . . . . . . . . . . . . . . . 375
Figure 66 ECL-compatible Schmitt trigger. . . . . . . . . . . . . . . . . . . . . . . . 377
Figure 67 Netlist for Schmitt trigger circuit. . . . . . . . . . . . . . . . . . . . . . . . 378
Figure 68 Hysteresis curve example: Schmitt trigger. . . . . . . . . . . . . . . . . . 379
Figure 69 Passive filter schematic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384
Figure 70 Current of L1 when R1 is 1.5 ohms. . . . . . . . . . . . . . . . . . . . . . 386
Figure 71 Rise time and overshoot vs. damping resistance. . . . . . . . . . . . . . . 387
Figure 72 RLC filter example circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . 388
Figure 73 Plot of capacitance versus bias voltage. . . . . . . . . . . . . . . . . . . . 390
Figure 74 Example schematic EXAMPLE.OPJ. . . . . . . . . . . . . . . . . . . . . . 392
xx

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Figures
Figure 75 Example schematic EXAMPLE.DSN. . . . . . . . . . . . . . . . . . . . . 398
Figure 76 Monte Carlo analysis setup for EXAMPLE.DSN. . . . . . . . . . . . . . 400
Figure 77 Summary of Monte Carlo runs for EXAMPLE.OPJ. . . . . . . . . . . . . 401
Figure 78 Parameter values for Monte Carlo pass three. . . . . . . . . . . . . . . . 402
Figure 79 Pressure sensor circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403
Figure 80 Model definition for RMonte1. . . . . . . . . . . . . . . . . . . . . . . . . 408
Figure 81 Pressure sensor circuit with RMonte1 and RTherm model definitions. . 409
Figure 82 Chebyshev filter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412
Figure 83 1 dB bandwidth histogram. . . . . . . . . . . . . . . . . . . . . . . . . . . 415
Figure 84 Center frequency histogram. . . . . . . . . . . . . . . . . . . . . . . . . . 416
Figure 85 Simple biased BJT amplifier. . . . . . . . . . . . . . . . . . . . . . . . . . 420
Figure 86 Amplifier netlist and circuit file. . . . . . . . . . . . . . . . . . . . . . . . 421
Figure 87 YatX Goal Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
Figure 88 Correct worst-case results. . . . . . . . . . . . . . . . . . . . . . . . . . . 423
Figure 89 Incorrect worst-case results. . . . . . . . . . . . . . . . . . . . . . . . . . 423
Figure 90 Schematic using VARY BOTH. . . . . . . . . . . . . . . . . . . . . . . . . 424
Figure 91 Circuit file using VARY BOTH. . . . . . . . . . . . . . . . . . . . . . . . 424
Figure 92 FILESTIM1 used on a schematic page. . . . . . . . . . . . . . . . . . . . 442
Figure 93 Circuit with a timing error . . . . . . . . . . . . . . . . . . . . . . . . . . 453
Figure 94 Circuit with a timing ambiguity hazard . . . . . . . . . . . . . . . . . . . 453
Figure 95 Mixed analog/digital circuit before and after interface generation. . . . 472
Figure 96 Simulation output for mixed analog/digital circuit. . . . . . . . . . . . 473
Figure 97 Timing ambiguity example one. . . . . . . . . . . . . . . . . . . . . . . . 479
Figure 98 Timing ambiguity example two. . . . . . . . . . . . . . . . . . . . . . . . 480
Figure 99 Timing ambiguity example three. . . . . . . . . . . . . . . . . . . . . . . 480
Figure 100 Timing ambiguity example four . . . . . . . . . . . . . . . . . . . . . . . 480
Figure 101 Timing hazard example. . . . . . . . . . . . . . . . . . . . . . . . . . . . 481
Figure 102 Convergence hazard example. . . . . . . . . . . . . . . . . . . . . . . . . 482
Figure 103 Critical hazard example. . . . . . . . . . . . . . . . . . . . . . . . . . . . 482
Figure 104 Cumulative ambiguity hazard example one. . . . . . . . . . . . . . . . . 483
Figure 105 Cumulative ambiguity hazard example two. . . . . . . . . . . . . . . . . 483
Figure 106 Cumulative ambiguity hazard example three. . . . . . . . . . . . . . . . 484
Figure 107 Reconvergence hazard example one. . . . . . . . . . . . . . . . . . . . . 485
Figure 108 Reconvergence hazard example two. . . . . . . . . . . . . . . . . . . . . 485
Figure 109 Glitch suppression example one. . . . . . . . . . . . . . . . . . . . . . . . 487
Figure 110 Glitch suppression example two. . . . . . . . . . . . . . . . . . . . . . . 487
Figure 111 Glitch suppression example three. . . . . . . . . . . . . . . . . . . . . . . 488
Figure 112 Analog and digital areas of a plot. . . . . . . . . . . . . . . . . . . . . . . 495
Figure 113 Two Probe windows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 496
Figure 114 Trace legend symbols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 530
Figure 115 Section information message box. . . . . . . . . . . . . . . . . . . . . . . 531
Figure 116 Example schematic EXAMPLE.OPJ. . . . . . . . . . . . . . . . . . . . . . 533
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Figures
Figure 117 Waveform display for EXAMPLE.DAT. . . . . . . . . . . . . . . . . . . . 534
Figure 118 Mixed analog/digital oscillator design . . . . . . . . . . . . . . . . . . . 537
Figure 119 Voltage at net 1 with y-axis added. . . . . . . . . . . . . . . . . . . . . . . 539
Figure 120 Mixed analog/digital oscillator results, . . . . . . . . . . . . . . . . . . . 540
Figure 121 Cursors positioned on a trough and peak of V(1) . . . . . . . . . . . . . 552
Figure 122 Waveform display for a persistent hazard. . . . . . . . . . . . . . . . . . 555
Figure A-1 Setpoints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 580
xxii